First Measurement of the Muon Neutrino Charged Current Single Pion Production Cross Section on Water with the T2K Near Detector

Abe, K. ; Andreopoulos, C. ; Antonova, M. ; et al.
2016.
Inspire Record 1465650 DOI 10.17182/hepdata.73182

The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ${\sim}0.8$~GeV. The differential measurements are presented as a function of muon and pion kinematics, in the restricted phase-space defined by $p_{\pi^+}>200$MeV/c, $p_{\mu^-}>200$MeV/c, $\cos \theta_{\pi^+}>0.3$ and $\cos \theta_{\mu^-}>0.3$. The total flux integrated $\nu_\mu$ charged current single positive pion production cross section on water in the restricted phase-space is measured to be $\langle\sigma\rangle_\phi=4.25\pm0.48~(\mathrm{stat})\pm1.56~(\mathrm{syst})\times10^{-40}~\mathrm{cm}^{2}/\mathrm{nucleon}$. The total cross section is consistent with the NEUT prediction ($5.03\times10^{-40}~\mathrm{cm}^{2}/\mathrm{nucleon}$) and 2$\sigma$ lower than the GENIE prediction ($7.68\times10^{-40}~\mathrm{cm}^{2}/\mathrm{nucleon}$). The differential cross sections are in good agreement with the NEUT generator. The GENIE simulation reproduces well the shapes of the distributions, but over-estimates the overall cross section normalization.

8 data tables

Total $\nu_\mu$ CC1$\pi^+$ cross section on water in the reduced phase-space of $p_{\pi^+} > 200$ MeV/$c$, $p_\mu > 200$ MeV/c, $\cos(\theta_{\pi^+}) > 0.3$ and $\cos(\theta_\mu) > 0.3$. The T2K data point is placed at the $\nu_\mu$ flux mean energy.

Unfolded $\nu_\mu$ CC1$\pi^+$ differential cross section as a function of $p_\pi$ in the reduced phase-space of $p_{\pi^+} > 200$ MeV/$c$, $p_\mu > 200$ MeV/c, $\cos(\theta_{\pi^+}) > 0.3$ and $\cos(\theta_\mu) > 0.3$.

Unfolded $\nu_\mu$ CC1$\pi^+$ differential cross section as a function of $\cos\theta_\pi$ in the reduced phase-space of $p_{\pi^+} > 200$ MeV/$c$, $p_\mu > 200$ MeV/c, $\cos(\theta_{\pi^+}) > 0.3$ and $\cos(\theta_\mu) > 0.3$.

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Measurement of the Multiple-Muon Charge Ratio in the MINOS Far Detector

The MINOS collaboration Adamson, P. ; Anghel, I. ; Aurisano, A. ; et al.
Phys.Rev. D93 (2016) 052017, 2016.
Inspire Record 1419065 DOI 10.17182/hepdata.77051

The charge ratio, Rμ=Nμ+/Nμ-, for cosmogenic multiple-muon events observed at an underground depth of 2070 mwe has been measured using the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly continuously from August 2003 until April 2012, comprise two independent data sets imaged with opposite magnetic field polarities, the comparison of which allows the systematic uncertainties of the measurement to be minimized. The multiple-muon charge ratio is determined to be Rμ=1.104±0.006(stat)-0.010+0.009(syst). This measurement complements previous determinations of single-muon and multiple-muon charge ratios at underground sites and serves to constrain models of cosmic-ray interactions at TeV energies.

1 data table

Efficiency-corrected charge ratios as a function of measured muon multiplicity, $M$.


Measurement of $R_{\text{uds}}$ and $R$ between 3.12 and 3.72 GeV at the KEDR detector

Anashin, V.V. ; Aulchenko, V.M. ; Baldin, E.M. ; et al.
Phys.Lett. B753 (2016) 533-541, 2016.
Inspire Record 1397002 DOI 10.17182/hepdata.76727

Using the KEDR detector at the VEPP-4M e+e− collider, we have measured the values of Ruds and R at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than 3.3% at most of energy points with a systematic uncertainty of about 2.1% . At the moment it is the most accurate measurement of R(s) in this energy range.

1 data table

Measured values of $R_{\rm{uds}}(s)$ and $R(s)$ with statistical and systematic uncertainties.


Study of Dynamics of $D^0 \to K^- e^+ \nu_{e}$ and $D^0\to\pi^- e^+ \nu_{e}$ Decays

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev. D92 (2015) 072012, 2015.
Inspire Record 1391138 DOI 10.17182/hepdata.74726

In an analysis of a 2.92~fb$^{-1}$ data sample taken at 3.773~GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be $\mathcal B(D^0 \to K^-e^+\nu_e)=(3.505\pm 0.014 \pm 0.033)\%$ and $\mathcal B(D^0 \to \pi^-e^+\nu_e)=(0.295\pm 0.004\pm 0.003)\%$. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element $f_{+}^K(0)|V_{cs}|=0.7172\pm0.0025\pm 0.0035$ and $f_{+}^{\pi}(0)|V_{cd}|=0.1435\pm0.0018\pm 0.0009$. Combining these products with the values of $|V_{cs(d)}|$ from the SM constraint fit, we extract the hadronic form factors $f^K_+(0) = 0.7368\pm0.0026\pm 0.0036$ and $f^\pi_+(0) = 0.6372\pm0.0080\pm 0.0044$, and their ratio $f_+^{\pi}(0)/f_+^{K}(0)=0.8649\pm 0.0112\pm 0.0073$. These form factors and their ratio are used to test unquenched Lattice QCD calculations of the form factors and a light cone sum rule (LCSR) calculation of their ratio. The measured value of $f_+^{K(\pi)}(0) |V_{cs(d)}|$ and the lattice QCD value for $f^{K(\pi)}_+(0)$ are used to extract values of the CKM matrix elements of $|V_{cs}|=0.9601 \pm 0.0033 \pm 0.0047 \pm 0.0239$ and $|V_{cd}|=0.2155 \pm 0.0027 \pm 0.0014 \pm 0.0094$, where the third errors are due to the uncertainties in lattice QCD calculations of the form factors. Using the LCSR value for $f_+^\pi(0)/f_+^K(0)$, we determine the ratio $|V_{cd}|/|V_{cs}|=0.238\pm 0.004\pm 0.002\pm 0.011$, where the third error is from the uncertainty in the LCSR normalization. In addition, we measure form factor parameters for three different theoretical models that describe the weak hadronic charged currents for these two semileptonic decays. All of these measurements are the most precise to date.

2 data tables

Summary of the range of each $q^2$ bin, the number of the observed events $N_{\rm observed}$, the number of produced events $N_{\rm produced}$, and the partial decay rate $\Delta\Gamma$ in each $q^2$ bin for $D^0\to K^-e^+\nu_e$ decays.

Summary of the range of each $q^2$ bin, the number of the observed events $N_{\rm observed}$, the number of produced events $N_{\rm produced}$, and the partial decay rate $\Delta\Gamma$ in each $q^2$ bin for $D^0\to \pi^-e^+\nu_e$ decays.


Study of the process $e^+e^-\to p\bar{p}$ in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector

The CMD-3 collaboration Akhmetshin, R.R. ; Amirkhanov, A.N. ; Anisenkov, A.V. ; et al.
Phys.Lett. B759 (2016) 634-640, 2016.
Inspire Record 1385598 DOI 10.17182/hepdata.73805

Using a data sample of 7.7 pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider we select about 2900 events of the process e+e−→pp¯ and measure its cross section at 12 energy points with about 6% systematic uncertainty. From the angular distribution of produced nucleons we obtain the ratio GE/GM .

2 data tables

The c.m. energy, beam energy shift, luminosity, number of selected $e^+e^- \to p\bar{p}$ events, detection efficiency, radiative correction, and cross section with statistical and systematic errors. The data for collinear type events.

The c.m. energy, luminosity, number of signal events, fraction of antiprotons stopped in beam pipe and DC inner shell, efficiency, cross section with statistical and systematic errors, for annihilation events.


Measurement of the $e^+ e^− \to \pi^+ \pi^−$ cross section between 600 and 900 MeV using initial state radiation

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Lett. B753 (2016) 629-638, 2016.
Inspire Record 1385603 DOI 10.17182/hepdata.73898

We extract the $e^+e^-\rightarrow \pi^+\pi^-$ cross section in the energy range between 600 and 900 MeV, exploiting the method of initial state radiation. A data set with an integrated luminosity of 2.93 fb$^{-1}$ taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider is used. The cross section is measured with a systematic uncertainty of 0.9%. We extract the pion form factor $|F_\pi|^2$ as well as the contribution of the measured cross section to the leading order hadronic vacuum polarization contribution to $(g-2)_\mu$. We find this value to be $a_\mu^{\pi\pi,\rm LO}(600-900\;\rm MeV) = (368.2 \pm 2.5_{\rm stat} \pm 3.3_{\rm sys})\cdot 10^{-10}$.

1 data table

Results of the BESIII measurement of the cross section $\sigma^{\rm bare}_{\pi^+\pi^-(\gamma_{\rm FSR})} \equiv \sigma^{\rm bare}(e^+e^-\rightarrow\pi^+\pi^-(\gamma_{\rm FSR}))$ and the squared pion form factor $|F_\pi|^2$. The errors are statistical only. The value of $\sqrt{s'}$ represents the bin center. The 0.9$\%$ systematic uncertainty is fully correlated between any two bins.


Measurement of azimuthal asymmetries in inclusive charged dipion production in $e^+e^-$ annihilations at $\sqrt{s}$ = 3.65 GeV

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev.Lett. 116 (2016) 042001, 2016.
Inspire Record 1384778 DOI 10.17182/hepdata.73802

We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process $e^+e^-\rightarrow \pi\pi X$ based on a data set of 62 $\rm{pb}^{-1}$ at the center-of-mass energy $\sqrt{s}=3.65$ GeV collected with the BESIII detector. These asymmetries can be attributed to the Collins fragmentation function. We observe a nonzero asymmetry, which increases with increasing pion momentum. As our energy scale is close to that of the existing semi-inclusive deep inelastic scattering experimental data, the measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon and are valuable to explore the energy evolution of the spin-dependent fragmentation function.

2 data tables

Results of $A_{\rm UL}$ and $A_{\rm UC}$ in each ($z_{1},z_{2}$) and $p_{t}$ bin. The averages $\langle z_i\rangle$, $\langle p_t\rangle$ and $\rm \frac{\langle sin^2\theta_{2}\rangle }{\rm \langle 1+cos^2\theta_{2} \rangle }$ are also given.

Results of $A_{\rm UL}$ and $A_{\rm UC}$ in each ($z_{1},z_{2}$) and $p_{t}$ bin. The averages $\langle z_i\rangle$, $\langle p_t\rangle$ and $\rm \frac{\langle sin^2\theta_{2}\rangle }{\rm \langle 1+cos^2\theta_{2} \rangle }$ are also given.


Observation of $Z_c(3900)^{0}$ in $e^+e^-\to\pi^0\pi^0 J/\psi$

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev.Lett. 115 (2015) 112003, 2015.
Inspire Record 1377204 DOI 10.17182/hepdata.73771

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, we observe a new neutral state Zc(3900)0 with a significance of 10.4σ. The mass and width are measured to be 3894.8±2.3±3.2  MeV/c2 and 29.6±8.2±8.2  MeV, respectively, where the first error is statistical and the second systematic. The Born cross section for e+e-→π0π0J/ψ and the fraction of it attributable to π0Zc(3900)0→π0π0J/ψ in the range Ec.m.=4.19–4.42  GeV are also determined. We interpret this state as the neutral partner of the four-quark candidate Zc(3900)±.

1 data table

Efficiencies, yields, $R=\frac{\sigma(e^+e^-\to\pi^0 Z_c(3900)^{0}\to\pi^0\pi^0 J/\psi)}{\sigma(e^+e^-\to\pi^0\pi^0 J/\psi)}$, and $\pi^0\pi^0 J/\psi$ Born cross sections at each energy point. For $N(Z_c^0)$ and $N(\pi^0\pi^0 J/\psi)$ errors and upper limits are statistical only. For $R$ and $\sigma_{\rm Born}$, the first errors and statistical and second errors are systematic. The statistical uncertainties on the efficiencies are negligible. Upper limits of $R$ (90$\%$ confidence level) include systematic errors.


Search for the isospin violating decay Y(4260)→J/ψηπ$^0$

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev. D92 (2015) 012008, 2015.
Inspire Record 1366025 DOI 10.17182/hepdata.73692

Using data samples collected at center-of-mass energies of s=4.009, 4.226, 4.257, 4.358, 4.416, and 4.599 GeV with the BESIII detector operating at the BEPCII storage ring, we search for the isospin violating decay Y(4260)→J/ψηπ0. No signal is observed, and upper limits on the cross section σ(e+e-→J/ψηπ0) at the 90% confidence level are determined to be 3.6, 1.7, 2.4, 1.4, 0.9, and 1.9 pb, respectively.

1 data table

Results on $e^{+}e^{-}\rightarrow J/\psi\eta\pi^{0}$. Listed in the table are the integrated luminosity $\cal{L}$, radiative correction factor (1+$\delta^{r}$) taken from QED calculation assuming the $Y(4260)$ cross section follows a Breit$-$Wigner line shape, vacuum polarization factor (1+$\delta^{v}$), average efficiency ($\epsilon^{ee}{\cal B}^{ee}$ + $\epsilon^{\mu\mu}{\cal B}^{\mu\mu}$), number of observed events $N^\text{obs}$, number of estimated background events $N^\text{bkg}$, the efficiency corrected upper limits on the number of signal events $N^\text{up}$, and upper limits on the Born cross section $\sigma^\text{Born}_\text{UL}$ (at the 90 $\%$ C.L.) at each energy point.


Observation of the Dalitz Decay $\eta' \to \gamma e^+e^-$

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev. D92 (2015) 012001, 2015.
Inspire Record 1364494 DOI 10.17182/hepdata.73672

We report the first observation of the Dalitz decay $\eta' \to \gamma e^+e^-$, based on a data sample of 1.31 billion $J/\psi$ events collected with the BESIII detector. The $\eta'$ mesons are produced via the $J/\psi \to \gamma \eta'$ decay process. The ratio $\Gamma(\eta' \to \gamma e^+ e^-)/\Gamma(\eta'\to\gamma\gamma)$ is measured to be $(2.13\pm0.09(\text{stat.})\pm0.07(\text{sys.}))\times10^{-2}$. This corresponds to a branching fraction ${\cal B}(\eta' \to \gamma e^+e^-)= (4.69 \pm0.20(\text{stat.})\pm0.23(\text{sys.}))\times10^{-4}$. The transition form factor is extracted and different expressions are compared to the measured dependence on the $e^+e^-$ invariant mass. The results are consistent with the prediction of the Vector Meson Dominance model.

2 data tables

Fitted ($n^{\text{obs}}_i$) and efficiency-corrected ($n^{\text{corr}}_i$) signal yields for the eight $M(e^+e^-)$ bins, and ratios ($r_i$). The uncertainties are statistical only.

Values of $|F|^2$ in each $M(e^+e^-)$ bin.


Measurement of the proton form factor by studying $e^{+} e^{-}\rightarrow p\bar{p}$

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev. D91 (2015) 112004, 2015.
Inspire Record 1358937 DOI 10.17182/hepdata.73442

Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of e+e-→pp¯ at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal (|GE|=|GM|). In addition, the ratio of electric to magnetic form factors, |GE/GM|, and |GM| are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at s=2232.4 and 2400.0 MeV and a combined sample at s=3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BABAR, improving the overall uncertainty by about 30%. The |GE/GM| ratios are close to unity and consistent with BABAR results in the same q2 region, which indicates the data are consistent with the assumption that |GE|=|GM| within uncertainties.

1 data table

Summary of the Born cross section $\sigma_\text{Born}$, the effective FF $|G|$, and the related variables used to calculate the Born cross sections at the different c.m.energies $\sqrt{s}$, where $N_\text{obs}$ is the number of candidate events, $N_\text{bkg}$ is the estimated background yield, $\varepsilon^\prime=\varepsilon\times(1+\delta)$ is the product of detection efficiency $\varepsilon$ and the radiative correction factor $(1+\delta)$, and $L$ is the integrated luminosity. The first errors are statistical, and the second systematic.


Measurement of the $e^{+}e^{-} \to \eta J/\psi$ cross section and search for $e^{+}e^{-} \to \pi^{0} J/\psi$ at center-of-mass energies between 3.810 and 4.600 GeV

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev. D91 (2015) 112005, 2015.
Inspire Record 1355215 DOI 10.17182/hepdata.73336

Using data samples collected with the BESIII detector operating at the BEPCII collider at 17 center-of-mass energies from 3.810 to 4.600 GeV, we perform a study of e+e-→ηJ/ψ and π0J/ψ. The Born cross sections of these two processes are measured at each center-of-mass energy. The measured energy-dependent Born cross section for e+e-→ηJ/ψ shows an enhancement around 4.2 GeV. The measurement is compatible with an earlier measurement by Belle.

3 data tables

Results on $e^{+}e^{-}\to\eta J/\psi$ in data samples in which a signal is observed with a statistical significance larger than $5\sigma$. The table shows the CM energy $\sqrt{s}$, integrated luminosity $\mathcal{L}_\mathrm{int}$, number of observed $\eta$ events $N^\mathrm{obs}_{\eta}(\mu^{+}\mu^{-})$/$N^\mathrm{obs}_{\eta}(e^{+}e^{-})$ from the fit, efficiency $\epsilon_{\mu}/\epsilon_{e}$, radiative correction factor $(1+\delta^{r})$, vacuum polarization factor $(1+\delta^{v})$, Born cross section $\sigma^{B}(\mu^{+}\mu^{-})$/$\sigma^{B}(e^{+}e^{-})$ and combined Born cross section $\sigma^{B}_\mathrm{Com}$. The first uncertainties are statistical and the second systematic.

Upper limits of $e^{+}e^{-} \to \eta J/\psi$ using the $\mu^{+}\mu^{-}$ mode. The table shows the CM energy $\sqrt{s}$, integrated luminosity $\mathcal{L}_\mathrm{int}$, number of observed $\eta$ events $N^\mathrm{sg}_{\eta}$, number of background from $\eta$ sideband $N^\mathrm{sb}_{\eta}$, and from $J/\psi$ sideband $N^\mathrm{sb}_{J/\psi}$, efficiency $\epsilon$, upper limit of signal number with the consideration of selection efficiency $N^\mathrm{up}_{\eta}/\epsilon$ (at the $90\%$ C.L.), radiative correction factor $(1+\delta^{r})$, vacuum polarization factor $(1+\delta^{v})$, Born cross section $\sigma^{B}$ and upper limit on the Born cross sections $\sigma^{B}_\mathrm{up}$ (at the $90\%$ C.L.). The first uncertainties are statistical and the second systematic.

Upper limits of $e^{+}e^{-} \to \pi^{0} J/\psi$. The table shows the number of observed events in the $\pi^{0}$ signal region $N^\mathrm{sg}$, number of events in $\pi^{0}$ sideband $N^\mathrm{sb}_{\pi^{0}}$, and in $J/\psi$ sideband $N^\mathrm{sb}_{J/\psi}$, efficiency $\epsilon$, the upper limit of signal events with the consideration of the selection efficiency $N^\mathrm{up}(\mu^{+}\mu^{-})/\epsilon$ (at the $90\%$ C.L.) and the upper limit of Born cross sections $\sigma^{B}_\mathrm{up}$ (at the $90\%$ C.L.).


Evidence for $e^+e^-\to\gamma\chi_{c1, 2}$ at center-of-mass energies from 4.009 to 4.360 GeV

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Chin.Phys. C39 (2015) 041001, 2015.
Inspire Record 1329785 DOI 10.17182/hepdata.72880

Using data samples collected at center-of-mass energies of √s = 4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process e(+)e(−) → γχ(c)J (J=0, 1, 2) and find evidence for e(+)e(−) → γχ(c1) and e(+)e(−) → γχ(c2) with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σ(B)(e(+)e(−) → γχ(c)J), as well as their upper limits at the 90% confidence level (C.L.) are determined at each center-of-mass energy.

3 data tables

The results on $e^+e^-\to\gamma\chi_{c0}$ Born cross section measurement. Shown in the table are the significance $\sigma$, detection efficiency $\epsilon$, number of signal events from the fits N$^{\rm obs}$, radiative correction factor ($1+\delta^{r}$), vacuum polarization factor ($1+\delta^{v}$), upper limit (at the 90$\%$ C.L.) on the number of signal events N$^{\rm UP}$, Born cross section $\sigma^{B}$ and upper limit (at the 90$\%$ C.L.) on the Born cross section $\sigma^{\rm UP}$ at different CME points. Numbers taken from journal version: some slight differences with respect to arXiv:1411.6336v1 in last two columns.

The results on $e^+e^-\to\gamma\chi_{c1}$ Born cross section measurement. Shown in the table are the significance $\sigma$, detection efficiency $\epsilon$, number of signal events from the fits N$^{\rm obs}$, radiative correction factor ($1+\delta^{r}$), vacuum polarization factor ($1+\delta^{v}$), upper limit (at the 90$\%$ C.L.) on the number of signal events N$^{\rm UP}$, Born cross section $\sigma^{B}$ and upper limit (at the 90$\%$ C.L.) on the Born cross section $\sigma^{\rm UP}$ at different CME points.

The results on $e^+e^-\to\gamma\chi_{c2}$ Born cross section measurement. Shown in the table are the significance $\sigma$, detection efficiency $\epsilon$, number of signal events from the fits N$^{\rm obs}$, radiative correction factor ($1+\delta^{r}$), vacuum polarization factor ($1+\delta^{v}$), upper limit (at the 90$\%$ C.L.) on the number of signal events N$^{\rm UP}$, Born cross section $\sigma^{B}$ and upper limit (at the 90$\%$ C.L.) on the Born cross section $\sigma^{\rm UP}$ at different CME points.


Energy Dependence of $K/\pi$, $p/\pi$, and $K/p$ Fluctuations in Au+Au Collisions from $\rm \sqrt{s_{NN}}$ = 7.7 to 200 GeV

The STAR collaboration Abdelwahab, N.M. ; Adamczyk, L. ; Adkins, J.K. ; et al.
Phys.Rev. C92 (2015) 021901, 2015.
Inspire Record 1322965 DOI 10.17182/hepdata.72254

A search for the quantum chromodynamics (QCD) critical point was performed by the STAR experiment at the BNL Relativistic Heavy Ion Collider, using dynamical fluctuations of unlike particle pairs. Heavy ion collisions were studied over a large range of collision energies with homogeneous acceptance and excellent particle identification, covering a significant range in the QCD phase diagram where a critical point may be located. Dynamical Kπ, pπ, and Kp fluctuations as measured by the STAR experiment in central 0–5% Au + Au collisions from center-of-mass collision energies sNN=7.7 to 200 GeV are presented. The observable νdyn was used to quantify the magnitude of the dynamical fluctuations in event-by-event measurements of the Kπ, pπ, and Kp pairs. The energy dependences of these fluctuations from central 0–5% Au + Au collisions all demonstrate a smooth evolution with collision energy.

1 data table

$p\pi$, Kp, and $K\pi$ fluctuations as a function of collision energy, expressed as $v_{dyn,p\pi}$, $v_{dyn,Kp}$, and $v_{dyn,K\pi}$ respectively. Shown are data from central (0-5%) Au+Au collisions at energies from $\sqrt{s_{\rm NN}}$ = 7.7 to 200 GeV from the STAR experiment.


Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

The STAR collaboration Adamczyk, L. ; Adamczyk, L. ; Adkins, J.K. ; et al.
Phys.Lett. B751 (2015) 233-240, 2015.
Inspire Record 1322126 DOI 10.17182/hepdata.73458

The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region , is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

14 data tables

Two-dimensional $\Delta\phi$ vs. $\Delta\eta$ correlation functions for charged hadron triggers from minimum-bias d+Au data at 200 GeV. All trigger and associated charged hadrons are selected in the respective pT ranges 4 < $p_T^{trig}$ < 5 GeV/c and 1.5 < $p_T^{assoc}$ < 4 GeV/c.

Two-dimensional $\Delta\phi$ vs. $\Delta\eta$ correlation functions for charged hadron triggers from 0-10% most-central Au+Au data at 200 GeV. All trigger and associated charged hadrons are selected in the respective pT ranges 4 < $p_T^{trig}$ < 5 GeV/c and 1.5 < $p_T^{assoc}$ < 4 GeV/c.

Two-dimensional $\Delta\phi$ vs. $\Delta\eta$ correlation functions for non-pion triggers from minimum-bias d+Au data at 200 GeV. All trigger and associated charged hadrons are selected in the respective pT ranges 4 < $p_T^{trig}$ < 5 GeV/c and 1.5 < $p_T^{assoc}$ < 4 GeV/c.

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Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in $\sqrt{s_{_{\rm NN}}} =$ 200 GeV Au+Au Collisions

The STAR collaboration Abdelwahab, N.M. ; Adamczyk, L. ; Adkins, J.K. ; et al.
Phys.Lett. B745 (2015) 40-47, 2015.
Inspire Record 1315466 DOI 10.17182/hepdata.73493

A data-driven method was applied to Au+Au collisions at sNN=200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δ η -dependent and Δ η -independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a Δ η -independent component of the correlation, which is dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity |η|<1 . In 20–30% central Au+Au collisions, the relative flow fluctuation was found to be 34%±2%(stat.)±3%(sys.) for particles with transverse momentum pT less than 2 GeV/c . The Δ η -dependent part, attributed to nonflow correlations, is found to be 5%±2%(sys.) relative to the flow of the measured second harmonic cumulant at |Δη|>0.7 .

27 data tables

The second harmonic two-particle cumulants for ($\eta_{\alpha}$, $\eta_{\beta}$ pairs for 20-30% central Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

The third harmonic two-particle cumulants for ($\eta_{\alpha}$, $\eta_{\beta}$ pairs for 20-30% central Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

The second harmonic four-particle cumulant for ($\eta_{\alpha}$, $\eta_{\alpha}$, $\eta_{\beta}$, $\eta_{\beta}$) quadruplets for 20-30% central Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

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Charged-to-neutral correlation at forward rapidity in Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev. C91 (2015) 034905, 2015.
Inspire Record 1311834 DOI 10.17182/hepdata.73610

<p>Event-by-event fluctuations of the multiplicities of inclusive charged particles and photons at forward rapidity in <inline-formula><mml:math><mml:mrow><mml:mi>Au</mml:mi><mml:mo>+</mml:mo><mml:mi>Au</mml:mi></mml:mrow></mml:math></inline-formula> collisions at <inline-formula><mml:math><mml:mrow><mml:msqrt><mml:msub><mml:mi>s</mml:mi><mml:mi mathvariant="italic">NN</mml:mi></mml:msub></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn></mml:mrow></mml:math></inline-formula> GeV have been studied. The dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidence of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as base lines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A nonzero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation owing to particle decay. Results are compared to the expectations based on the generic production mechanism of pions owing to isospin symmetry, for which no significant (<inline-formula><mml:math><mml:mrow><mml:mo>&lt;</mml:mo><mml:mn>1</mml:mn><mml:mo>%</mml:mo></mml:mrow></mml:math></inline-formula>) deviation is observed.</p>

21 data tables

Multiplicity distributions of raw charged particles and photons.

The $v_{dyn}$ and the three terms of $v_{dyn}$ vs $\sqrt{\langle N_{ch}\rangle \langle N_{\gamma}\rangle }$ for real events. $\omega_{ch}^{real}$ is plotted.

The $v_{dyn}$ and the three terms of $v_{dyn}$ vs $\sqrt{\langle N_{ch}\rangle \langle N_{\gamma}\rangle }$ for mixed events. $\omega_{ch}^{mixed}$ is plotted.

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$\Lambda\Lambda$ Correlation Function in Au+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 114 (2015) 022301, 2015.
Inspire Record 1311513 DOI 10.17182/hepdata.73492

We present $\Lambda\Lambda$ correlation measurements in heavy-ion collisions for Au+Au collisions at $\sqrt{s_{NN}}= 200$ GeV using the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). The Lednick\'{y}-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the $\Lambda\Lambda$ correlation function and interaction parameters for di-hyperon searches are discussed.

4 data tables

The invariant mass distribution for $\Lambda$ and $\bar{\Lambda}$ produced in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, for 0-80% centrality. The $\Lambda$ and $\bar{\Lambda}$ candidates lying in the mass range 1.112 to 1.120 GeV/c^2 were selected for the correlation measurement.

The $\Lambda\Lambda$ and $\bar{\Lambda}\bar{\Lambda}$ correlation function in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, for 0-80% centrality.

The combined $\Lambda\Lambda$ and $\bar{\Lambda}\bar{\Lambda}$ correlation function for 0-80% centrality Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

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Elliptic flow of non-photonic electrons in Au+Au collisions at $\sqrt{s_{\rm NN}} = $ 200, 62.4 and 39 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
2014.
Inspire Record 1298024 DOI 10.17182/hepdata.77016

We present the measurements of elliptic flow ($v_2$) of non-photonic electrons (NPE) by the STAR experiment using 2- and 4-particle correlations, $v_2${2} and $v_2${4}, and the event plane method in Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV, and $v_2${2} at 62.4 and 39 GeV. $v_2${2} and $v_2${4} are non-zero at low and intermediate transverse momentum ($p_T$) at 200 GeV, and $v_2${2} is consistent with zero at low $p_T$ at other energies. For Au+Au collisions at $p_T<1$ GeV/c, there is a statistically significant difference between $v_2${2} at 200 GeV and $v_2${2} at the two lower beam energies.

18 data tables

Signal-to-background (S/B) ratio as a function of transverse momentum, Au+Au 200 GeV, 0-60% central events with minimum bias trigger

Signal-to-background (S/B) ratio as a function of transverse momentum, Au+Au 200 GeV, 0-60% central events with with High Tower (high pT) trigger

Signal-to-background (S/B) ratio as a function of transverse momentum, Au+Au 39 GeV, 0-60% central events with minimum bias trigger

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Precision Measurement of the Longitudinal Double-spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at $\sqrt{s}=200$ GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 115 (2015) 092002, 2015.
Inspire Record 1297229 DOI 10.17182/hepdata.73432

We report a new high-precision measurement of the mid-rapidity inclusive jet longitudinal double-spin asymmetry, $A_{LL}$, in polarized $pp$ collisions at center-of-mass energy $\sqrt{s}=200$ GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep inelastic scattering (DIS), semi-inclusive DIS, and RHIC $pp$ data. The measured asymmetries provide evidence for positive gluon polarization in the Bjorken-$x$ region $x>0.05$.

7 data tables

Jet neutral energy fraction (NEF) comparing data with simulations, where both are calculated with pT subtraction. This plot shows 8.4 < $p_T$ < 9.9 GeV/c.

Jet neutral energy fraction (NEF) comparing data with simulations, where both are calculated with pT subtraction. This plot shows 26.8 < $p_T$ < 31.6 GeV/c.

Inclusive jet $A_{LL}$ vs. parton jet $p_T$ for |eta|<0.5.

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Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 113 (2014) 072301, 2014.
Inspire Record 1292792 DOI 10.17182/hepdata.73441

We report measurements of single- and double- spin asymmetries for $W^{\pm}$ and $Z/\gamma^*$ boson production in longitudinally polarized $p+p$ collisions at $\sqrt{s} = 510$ GeV by the STAR experiment at RHIC. The asymmetries for $W^{\pm}$ were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton's polarized quark distributions at the scale of the $W$ mass. The results are compared to theoretical predictions, constrained by recent polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range $0.05<x<0.2$.

13 data tables

$E_T^e$ distribution of $W^{\pm}$ candidate events, background contributions, and sum of backgrounds and W -> ev MC signal. This plot is for Electron |eta|<0.5.

$E_T^e$ distribution of $W^{\pm}$ candidate events, background contributions, and sum of backgrounds and W -> ev MC signal. This plot is for Electron 0.5<|eta|<1.1.

$E_T^e$ distribution of $W^{\pm}$ candidate events, background contributions, and sum of backgrounds and W -> ev MC signal. This plot is for Positron |eta|<0.5.

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Observation of $D^0$ Meson Nuclear Modifications in Au+Au Collisions at $\sqrt{s_{NN}}=200$  GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 113 (2014) 142301, 2014.
Inspire Record 1292132 DOI 10.17182/hepdata.73474

We report the first measurement of charmed-hadron ($D^0$) production via the hadronic decay channel ($D^0\rightarrow K^- + \pi^+$) in Au+Au collisions at $\sqrt{s_{_{\mathrm{NN}}}}$ = 200\,GeV with the STAR experiment. The charm production cross-section per nucleon-nucleon collision at mid-rapidity scales with the number of binary collisions, $N_{bin}$, from $p$+$p$ to central Au+Au collisions. The $D^0$ meson yields in central Au+Au collisions are strongly suppressed compared to those in $p$+$p$ scaled by $N_{bin}$, for transverse momenta $p_{T}>3$ GeV/$c$, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate $p_{T}$ is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

3 data tables

Centrality dependence of the $D^0$ $p_T$ differential invariant yield in Au+Au collisions.

$D^0\,R_{AA}$ for different centralities.

Integrated $D^0$ $R_{AA}$ as a function of $N_{part}$ in different $p_T$ regions.


Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 113 (2014) 052302, 2014.
Inspire Record 1288917 DOI 10.17182/hepdata.73457

Local parity-odd domains are theorized to form inside a Quark-Gluon-Plasma (QGP) which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect (CME). The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this paper, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39 and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy, and tends to vanish by 7.7 GeV. The implications of these results for the CME will be discussed.

15 data tables

The three-point correlator, $\gamma$, as a function of centrality for Au+Au collisions at 62.4 GeV.

The three-point correlator, $\gamma$, as a function of centrality for Au+Au collisions at 39 GeV.

The three-point correlator, $\gamma$, as a function of centrality for Au+Au collisions at 27 GeV.

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Study of $e^+e^−$ → $p\bar{p}$ in the vicinity of ψ(3770)

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Lett. B735 (2014) 101-107, 2014.
Inspire Record 1286898 DOI 10.17182/hepdata.64597
2 data tables

Summary of results at center-of-mass energies from 3.65 to 3.90 GeV. N(SIG) is the number of E+ E- --> P P events; EPSILON is the detection efficiency; L is the integrated luminosity; (1 + DELTA)(DRESSED) is the initial state radiation correction factor without the vacuum polarization correction; and SIG(OBS), SIG(DRESSED) and SIG(BORN) are the observed cross section, the dressed cross section and the Born cross section, respectively.

The two solutions of the dressed cross section and the corresponding phase angles, PHI.


Dielectron Mass Spectra from Au+Au Collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 113 (2014) 022301, 2014.
Inspire Record 1275614 DOI 10.17182/hepdata.95663

We report the STAR measurements of dielectron ($e^+e^-$) production at midrapidity ($|y_{ee}|<$1) in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200\,GeV. The measurements are evaluated in different invariant mass regions with a focus on 0.30-0.76 ($\rho$-like), 0.76-0.80 ($\omega$-like), and 0.98-1.05 ($\phi$-like) GeV/$c^{2}$. The spectrum in the $\omega$-like and $\phi$-like regions can be well described by the hadronic cocktail simulation. In the $\rho$-like region, however, the vacuum $\rho$ spectral function cannot describe the shape of the dielectron excess. In this range, an enhancement of 1.77$\pm$0.11(stat.)$\pm$0.24(sys.)$\pm$0.33(cocktail) is determined with respect to the hadronic cocktail simulation that excludes the $\rho$ meson. The excess yield in the $\rho$-like region increases with the number of collision participants faster than the $\omega$ and $\phi$ yields. Theoretical models with broadened $\rho$ contributions through interactions with constituents in the hot QCD medium provide a consistent description of the dilepton mass spectra for the measurement presented here and the earlier data at the Super Proton Synchrotron energies.

11 data tables

Uncorrected Distributions of e+ e- invariant mass, the reconstructed background, and the signal pairs in 200 GeV Au+Au minimum bias collisions.

The ratio of signal to background in Au + Au collisions at $\sqrt{s_{{NN}}}$ = 200 GeV (Minimum Bias).

The ratio of signal to background in Au + Au collisions at $\sqrt{s_{{NN}}}$ = 200 GeV (Central).

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